1. Field of the Invention
This invention relates to a power shovel dipper or bucket which has a fastening device which pivotally connects a door to the dipper and the dipper to a handle about a common axis.
2. Description of the Prior Art
A dipper is commonly used on a power shovel or other power source excavating device for the purpose of moving earth, rock or ore. Among its many applications are mining, quarrying, road building and maintenance, building excavating, digging trenches or pipelines, etc. Dippers used on power shovels commonly have an open front for receiving material and a door which is pivotally attached to the back of the dipper for discharging material. The dipper is pivotally attached to one end of a handle which, in turn, is secured to the power shovel boom.
On some dippers, the pivot axis for the connection of the door to the dipper is the same as the pivot axis for the connection of the dipper to the handle. This permits the use of a common fastening device to pivotally attach the door to the dipper and the dipper to the handle.
Dippers are subjected to a great deal of impact, abrasion and wear. Consequently, many of the components of a dipper, such as the front casting, heel band and door, are designed to be rebuilt or replaced. In order to repair a dipper, it must be removed from the machine to which it is attached so that it can be transported to a repair facility. In order to remove the dipper from its handle, the fastening device, which is commonly a pin, is removed. If the same pin is also used to pivotally connect the door to the dipper, the door will become detached from the dipper.
It is desirable to retain the door on the dipper after the dipper is removed from its handle so that the dipper and door can be transported as a unitary structure. If the door is separated from the dipper, it requires special handling and large doors may have to be transported on a truch separate from the one transporting the dipper.
To avoid having to separately handle and transport the dipper and the door where a common fastening device mounts the door on the dipper and the dipper on the power shovel handle, it is common practice to weld the door to the dipper before the fastening device is removed. After the dipper has been repaired, it is again connected to the handle by the fastening device, which also connects the door to the dipper. Subsequent to the re-installation of the device, the welds which connect the door to the dipper are ground off to restore the door to its operating condition.
It is desirable to provide a fastening device for pivotally connecting the door to the dipper and the dipper to the handle which permits the dipper to be separated from the handle without detaching the door from the dipper.